The present invention relates to a printer for a data-processing machine. More particularly this invention concerns such a printer useable in a data-processing machine having a single operator station and set up to print on form bands.
In such a machine the form band or bands are generally pulled out of a pile, printed on, and then loaded into another pile. These bands are usually formed as zig-zag pleated stacks so that at each end the form band can be formed into a neat pile of compact shape. Normally perforations are formed between the individual sheets, so that, if necessary, the printed result can be separated into handy pages.
A data-processing machine with single operator station can include any of the machines used for pre-data-processing operations, as for example billing, bookkeeping, finance-accounting and the like. Such machines are not used in conjunction with external memories or another computer. Thus, such a machine carries out all of its own operations, and is typically referred to as a bookkeeping machine, although it can be readily applied to many other types of tasks, for instance such machines can be used for statistical analysis, in scientific work for recording and analyzing results, for billing and preparing payrolls, for studying operating efficiency in a plant, or calculating profit and the like. Nevertheless such machines are relatively simple in their operation and are self-contained. The necessary types of operations can be programmed right into the machine.
As a rule with such machines the data being processed is continuously printed out. It can also be entered on magnetic cards, and indeed frequently both such permanent records are used. Usually the form band at least is printed right under the operator's eyes. To this end it must be drawn from a supply somewhere into a location easily viewable by the operator sitting at his input station and printed at this station. Thus the band must frequently follow a very circuituous path between the supply and the receptacle in which it eventually terminates. When the band runs out, it is necessary for a rather complicated threading operation to be carried out in order to feed new band in. Furthermore, the feed for the magnetic cards is frequently rather long so that in case one of the cards jams up in the machine, it is necessary to shut down the data-processing operation for the time it takes to clear the problem. With both such systems, form bands and magnetic cards, the longer path the item must follow the greater is the chance of mishap. Furthermore, the longer the feeding path the more drive rollers or the like are needed for the form band in order to hold it tight at the printing location and insure proper spacing between adjacent rows of printing.
It is known to have a system wherein the information is entered first on a so-called control screen. The operator can then verify if the entry is correct and if it is he can push an enter button which causes the machine to transfer this information from the control screen to the printed record. If an error is discovered it is corrected before the enter button is actuated. Thus, with such an arrangement it is not necessary continuously to oversee the printing operation. The only occasions for looking at the actual matter being printed are, for example, after a work break in order to ascertain just where the data-processing operation was stopped.
Even though such systems are known almost invariably the form band is passed through a circuituous path to the printer, and then away from the printer to the receptacle in which it is loaded after printing. Since the printer is almost invariably mounted at eye-level it is typically necessary to have the band run vertically at least in the eye-level printing location and then passed to the receptacle. Thus the form band must be bent back and forth through 180 degrees at least once, increasing the possibility of tearing this form and occasionally leading to separation at the inter-page perforations.